The sintering process difference of MoSi 2 , NbSi 2 and (Mo 1-x ,Nb x )Si 2 solid solution

Abstract

The dilatometric sintering process experimental results of pure niobium disilicides, molybdenum disilicides, 50wt.MoSi 2 + 50wt.%NbSi 2 solid-phases mixtures and (Mo 1-x ,Nb x )Si 2 were presented. Both MoSi 2 and NbSi 2 were synthesised by magnesium-thermal synthesis (Plasmotherm LLC). The solid solution (Mo 1-x ,Nb x )Si 2 were synthesised by self-propagating high-temperature synthesis (SHS) (ISMAN RAS). The shrinkage curves analysis of MoSi 2 and NbSi 2 showed the similar shrinkage curve relief. The pure MoSi 2 relative shrinkage is greater than NbSi 2 under the same conditions at 1900°C in Ar atmosphere. The two disilicides mixture shrinkage curve shifted T onset to a higher temperature region relatively pure disilicides. The (Mo 1-x ,Nb x )Si 2 solid solution had a completely different shrinkage curve, it was characterised by a pick at 305°C and a double kink in the sintering process corresponded to the passage of two successive sintering processes. The solid solution shrinkage curve was different both NbSi 2 and MoSi 2 and there was (Mo 1-x ,Nb x )Si 2 phase transition at 305°C.